Method for treating surfaces of building materials

ABSTRACT

Building materials are treated with a flux and then heated with a high temperature flame in order to provide a decorative, durable glazed surface. Especially useful for inexpensive building materials such as low density bricks made from slag or other waste materials.

United States Patent 1191 Dulat 1 1 Feb. 6, 1973 METHOD FOR TREATINGSURFACES I OF BUILDING MATERIALS [75] Inventor: Joseph Dulat, Syrena,England 7 [73] Assignee: United States Borax & Chemical Corporation, LosAngeles, Calif.

22 Filed: Jan; 25, 1971 [21] 7 Appl. No.: 109,682

[52] U.S.C1 ..117/46 FC, 117/21, 117/123 A, 117/123 B, 117/123 C,117/125 [51] Int. Cl. ..B44d l/44 [581 Field of Search...l 17/123 A, 123B, 123 C, 125, 117/46 FC [56] References Cited UNITED STATES PATENTS468,321 2/1892 Anderson ..117/125 X 2,663,658 12/1953 SCharecht v. ....117/125 X 2,741,565 4/1956 Halversen et a1. l7/l25 X 4/1956 Snoddy..117/125 X 3,144,344 8/1964 Unhoefer ..117/125 X 2,634,219 4/1953 Smith..117/125 2,562,477 7/1951 Ramsay .4 ...1l7/l25 X 1,959,149 5/1934 Baggset a1. ..117/125 3,402,060 9/1968 Groskaafmanis.... ..1 17/125 X2,587,152 2/1952 Harlan et a1. ...1 17/125 X 2,832,695 4/1958 Compton eta1, 17/125 X Primary ExaminerWi1liam D. Martin Assistant Examiner-M. R.Lusignan Att0rney.lames R. Thornton [57] ABSTRACT Building materials aretreated with a flu x and then heated with a high temperature flame inorder to provide a decorative, durable glazed surface. Especially usefulfor inexpensive building materials such as low density bricks made fromslag or other waste materials.

6 Claims, No Drawings METHOD FOR TREATING SURFACES OF BUILDING MATERIALSThis invention relates to an improved method for the treatment ofbuilding materials by heating with a flame in order to provide adecorative and more durable surface.

It is known that by applying heat in the form of a flame to the surfaceof building materials it is possible to produce a decorative surface.Examples of materials which may be treated in this way include concrete(both high density and aerated), bricks, tiles, and other similarsubstances, such as cement-lime-sand compositions. Concrete is generallybased on Portland Cement which contains calcium silicate and/or calciumaluminate. The application of a flame to the surface of such materialsfor about 30 second produces, however, a poor quality glaze which isusually marred by specks of white efflorescence.

The present invention provides an improved process whereby a betterglaze is produced, the time of heating required to produce the glaze isreduced,,and the natural color of the material is improved or modified.Also, unlike conventional glazing procedures, the method of thisinvention is applicable to construction materials in situ, that is, tothe walls of an existing building. It is especially useful for producinga decorative, durable glazed surface on low density bricks made fromslag or other waste materials.

The present method comprises treating the surface of the buildingmaterial, prior to heating, with a fluxing material. The treated surfaceis then heated with a flame, preferably at a temperature of at leastabout l,500 C. By the application of a fluxing material it is possibleto reduce the time of heating by up to about 30%.

Preferred fluxing materials are the inorganic and organic borates suchas the alkali and alkaline earth metal borates, boric acid, the borateesters and glycol-borate condensation products sold under the same ofLIQUIBOR. However, other well-known fluxing agents can also be used suchas silica, Cornish Stone, Nepheline syenite, felspar, pegmatite, and thephosphates and silicates of the alkali and alkaline earth metals.

The fluxing material can be applied in the form of a powder or as asolution or a suspension in a liquid carrier such as water or kerosene.It is applied either directly to the untreated surface of a buildingmaterial or may be applied to the surface of such material which haspreviously been treated with an adhesive substance.

Other materials can also be applied to the surface of the material priorto flame treatment or included in the fluxing mixture, such as metaloxides, metal borates, boron-containing frits, or other compounds whichwill yield a metal oxide under the conditions of the process, therebymodifying the color or surface properties of the treated buildingmaterial. The metal oxides will impart a different color to the glazedproduct which is readily adjusted by choice of the particular metaloxide employed. For example, cobalt oxide will produce a bluecoloration. The following examples illustrate the method of the presentinvention.

EXAMPLE Four 2-inch cubes of concrete were treated accordin to theresent invention b a l in the a ro riate afditive ai'hd heating the treate riitaze at zy em perature of about 1,500 C. with an oxygen-coal gastorch for the periods of time shown in the following table. Only oneface of each cube was treated. The additives were applied as a paste inkerosene to block numbers B, C, and D. Block number E was treated withborax powder, together with 5 percent by weight of waterglass. Blocknumber F was treated with calcium borate (colemanite) applied as anaqueous suspension containing 5 percent by weight of water-glass. Thefollowing results were obtained:

(1) Greenish surface, mediocre glazing marred with specks of whiteefflorescence.

(2) Greenish surface, good glazing.

(3) Blue surface, mediocre glazing marred with specks of whiteefflorescence.

(4) Blue surface, good glazing.

Various changes and modifications of the invention can be made and, tothe extent that such variations incorporate the spirit of thisinvention, they are intended to be included within the scope of theappended claims.

What is claimed is:

1. The method for providing a decorative, durable, glazed surface onexisting building materials of brick, concrete or cement-lime-sandcompositions, which comprises treating the surface of said buildingmaterials with a borate fluxing material and then applying heat to thetreated surface with a flame at a temperature of at least about 1,500 C.for up to about 30 seconds.

2. The method in accordance with claim 1 in which the building materialis treated with said borate in combination with a metal oxide prior toheating, thereby modifying the color of the resultant glazed buildingmaterial.

3. The method in' accordance with claim 1 in which the treated surfaceof said building material is heated

1. The method for providing a decorative, durable, glazed surface onexisting building materials of brick, concrete or cement-lime-sandcompositions, which comprises treating the surface of said buildingmaterials with a borate fluxing material and then applying heat to thetreated surface with a flame at a temperature of at least about 1,500*C. for up to about 30 seconds.
 2. The method in accordance with claim 1in which the building material is treated with said borate incombination with a metal oxide prior to heating, thereby modifying thecolor of the resultant glazed building material.
 3. The method inaccordance with claim 1 in which the treated surface of said buildingmaterial is heated with an oxygen-coal gas torch.
 4. The method inaccordance with claim 1 in which said building material is a low densitybrick made from slag.
 5. The method in accordance with claim 1 in whichsaid fluxing material is borax.